Many agricultural fertilizers are granulated and dried after formulation to provide the fertilizer in a stable and easily handled form. An inherent drawback of the conventional granulation and drying process is that a significant portion of the fertilizer is broken down into dust. The fertilizer can also be further broken down during packaging, transport, and storage. Fertilizer with increased dusting is significantly more difficult to handle and distribute on the fields to be treated, as the dust is prone to becoming airborne such that its application is difficult to control.
In addition to wasting otherwise useful fertilizer, in some circumstances, the dust from the fertilizer creates a substantial safety risk as the chemical makeup of many fertilizers is highly reactive and can explode if ignited. The dust particulates can be easily ignited by a small spark and even by discharge of static electricity. Accordingly, the fertilizer granules are often coated with an anti-dust coating that reduces or entraps the dust created during the granulation or transport.
The anti-dust coating often comprises petroleum or other oil-based liquids that are sprayed onto the fertilizer granules to adhere any dust particulates formed, during granulation or transport, for example, to the larger fertilizer granules. The oil-based coating also encapsulates the dust particulates to prevent or inhibit the dust particulates from becoming airborne.
While oil-based coatings are effective at controlling the dust particulates, the inherent drawback of the oil-based coatings is that the coatings have a limited effective shelf-life and can have diminishing effectiveness as the coating ages. In particular, the coating itself can become dried with age and contribute to, rather than control, the dust problems. Accordingly, this can results in a significantly shortened shelf life of the fertilizer. Alternatively, prolonged storage or transport of the coated fertilizer can present a greater safety risk as the storage or transport time may have exceeded the effective life of the coating resulting in unsafe fertilizer products. As such, there is a need for prolonging the effectiveness of oil-based dust control particulates.